This 325 gsm card is flexible and springs back to shape, so I tried making a variant of the cone lampshade, using a flat card ribbon instead of a dowel rod to tie the ends together.
With some care I think good results could be achieved, but in this case I found it creased too readily.
This joint methods also requires wider slots than this pictured in the first picture; I widened them with a craft knife after laser-cutting the template.